Acute carnosine and β-alanine supplementation increases the compensated part of the ventilation vs work rate relationship during a ramp incremental cycle test in physically active men

Background. Chronic supplementation with carnosine and β-alanine (Carn-βA) has been proposed to improve muscle contractility and reduce muscle fatigue mainly through an increase in intracellular pH buffering capacity. However, the acute ergogenic effects of Carn-βA supplementation are poorly investigated. This study aimed at evaluating the acute effects of a single Carn-βA supplementation on the cardiorespiratory and metabolic response during a ramp cycle-ergometric test. Methods. This randomized, double-blind, placebo-controlled study, involved 10 healthy males (age 22.2±1.9 years, body mass 72.5±7.9 kg, stature 1.72±0.08 m, body mass index, 24.47±1.91 kg/m2, mean±standard deviation). All the participants performed two maximal incremental ramp tests on a cycle ergometer, with a prior randomized assumption of 2.5 g L-carnosine plus 2.5 g β-alanine (Carn-βA) or placebo (PLA). During exercise, gas exchange parameters were measured breath-by-breath, heart rate was monitored by electrocardiography and rate perceived exertion was determined on Borg scales. From the ramp test, peak cardiorespiratory and metabolic parameters and ventilatory thresholds (VT1 and VT2) were calculated off-line. Results. No differences between the experimental conditions emerged at peak exercise. However, despite acute Carn-ßA supplementation did not affect the single ventilatory thresholds, the compensated portion of the ramp test (i.e., the difference between VT2 and VT1) was significantly larger (P = 0.043) in Carn-ßA. Conclusions. These findings demonstrate a positive effect of acute Carn-ßA supplementation on the compensated part of the exercise. This should be taken into account by nutritionists and athletes searching for nutritional supplements, when a quick effect based on an acute dose is required.